DPRK: Legitimacy through Isolation

It appears that the new President of South Korea, Lee Myung-bak, is taking steps towards reconciling with his neighbors in the North, the bizarre 1950's-themed zone known as "The Democratic People's Republic of Korea," more commonly called North Korea. Reunification has long been a central issue in South Korean politics, and from what little we in the world outside the DPRK know, is a central platform of the Juche (the official North Korean political philosophy) idea. Whereas previous generations of South Koreans, many of whom were veterans and survivors of the civil war there in the 1950's generally felt bitter towards the government of the Great Leader (as he is known in the DPRK) Kim Il-Sung and his son (known as the "Dear Leader") Kim Jung-Il. Having seen how the isolationist and repressive policies of the Communist regime there has created extreme hardship not only for those individuals unfortunate enough not to have fled out of the country before the war's end, but also for the friends and families of those trapped inside, many older South Koreans did and still do support a hard-line policy towards the North Korean government. Younger generations of nationalistic and not so staunchly pro-American South Koreans, however, have increasingly begun to call for dialog with their northern brothers, with whom they are still technically at war.
Reflecting this desire among South Koreans for communication with the DPRK is the newly-elected president of South Korea, Lee Myung-bak. He has recently made the news for advocating the creation of permanent liason offices in the two countries' capitals in order to ease communication and perhaps move towards larger and better things. The United States has encouraged the South Korean government to do this for several years, however, only now has the President been politically able to actually carry it out. His predecessor, Roh Moo-hyun, although generally more conciliatory in nature towards the DPRK, lost too much credibility for supporting the United States' presence in Iraq to be able to make any significant steps towards presenting a friendlier policy towards the DPRK.
What is perhaps more interesting than the President Lee's move, however, is the North Korean government's complete denial of the efforts towards national reconciliation. Not only has the DPRK government refused to acknowledge Lee's efforts, but it continues to paint Lee, and the South Korean government in general, as "kicking up an anti-DPRK nuclear racket," choosing to continue pressing the nuclear disarmament issue. This article, from the North Korean government-controlled Korean Central News Agency, contains several gems that demonstrate just how much North Korean cares for an individual who is breaking norms in order to make a gesture of goodwill, labeling him, among other things, "traitor Lee," "a diehard moneygrubber and a swindler," and a "sycophantic traitor". This might be surprising, considering that the government of the DPRK has consistently called for national reunification since the country's split half a century ago. This leads us to ask, if the DPRK government genuinely wants reunification, then why do they ignore South Korean's efforts to reach out to them, and even paint them as aggressors?
Such seemingly illogical behavior can be better interpreted in terms of North Korea's domestic affairs. North Korea, in order to legitimize its ridiculously large army, known as the world's largest antiquated military, needs to give its military some sort of purpose, considering that North Korea has not actually participated in any major military conflict since the end of the war. The DPRK government tends to justify the existence of its army on the idea that it is used not only to ward off the evil, imperialistic United States, but also to eventually move into the South and reunify the country by force. Obviously, North Korea will not be able to take the South by force, especially with the United States still staffing the Demilitarized Zone. Now, since the idea of invading South Korea successfully is so far fetched that not even North Korean military commanders have attempted it in the past half a century, it is obvious that such rhetoric is designed solely to keep the populace, which lives in the world's most repressed economy and arguably most oppressive political system, complacent. The DPRK government realizes that if the country unifies, it will not be under the banner of Juche, but rather under a more democratic regime. Therefore, any efforts to reconciliation made by the South must be repudiated. In other words, it's in the North Korean government's best interests to continue isolating itself from the South and from the rest of the world, lest their Dear Leader lose his dictatorial grip over the people. This case clearly demonstrates that moves towards international cooperation, perhaps even leading to a security community, can and will be blocked by national leaders seeking legitimacy through the continuation of strained relations.
Here is an interesting and bizarre documentary made by an American who sneaked into North Korea recently.